Multiple Fields Color Theme Add-In (beta)

The Color Theme (Multiple Fields) add-in provides you with a new way to visualize and compare multiple fields of data. Also known as plurality maps, predominance maps, relationship maps, bivariate maps, or multivariate maps, multiple field themes can reveal patterns and let you see how items are connected. This is achieved using a method known as multivariate choropleth mapping, in which multiple color ramps merge to display all pattern combinations in a grid-like legend.

To install:*

1. Download the file color-theme-multiple-fields-addin.exe.
2. Double click the executable to launch the installation.
3. Confirm that you would like to allow the installer to make changes to your PC and follow the instructions in the installation wizard.
4. Once installed, the add-in can be launched by opening a Maptitude map and choosing Tools>GIS Developer's Kit>Add-Ins>Color Theme (Multiple Fields).

*NOTE: The Color Theme (Multiple Fields) add-in works only with latest version of Maptitude.

To Add a Multiple Fields Color Theme to a Map

1. Make an area layer the working layer by choosing it from the drop-down list on the Standard toolbar or right-clicking in the Display Manager and choosing Make Working Layer.
2. Choose Tools>GIS Developer's Kit>Add-Ins> Color Theme (Multiple Fields) to display the Color Theme (Multiple Fields) dialog box.
3. Choose whether to apply the theme to All Records or a selection set using the Records drop-down list.
4. Click Choose Fields to display the Choose Fields dialog box.
5. Highlight up to ten fields in the Available Fields scroll list and click Add>> and then click OK.
6. MapWizard fills in the other settings in the dialog box. Modify any of the other settings as follows:

   To do this...	Do this...
   Change the legend labels for a theme class	Edit the text in the Label column
   Change the color of the theme class palette	Choose a color from the drop-down list in the Color column
   Choose the total field to convert to percentages	Choose a field from the Denominator drop-down list (e.g., population, households)
   Change the number of ranges	Choose from the # of Classes drop-down list
   Modify the ranges for the classes	Enter different values in the Low % or High % columns

7. Click OK. Maptitude draws the map with the color theme and displays a legend.

Try it Yourself

1. Choose File>New Workspace, choose to create a new map of the United States, then click OK, and Finish.
2. If the County layer is autoscaled off, make it visible and make it the working layer.
3. Choose Tools>GIS Developer's Kit>Add-Ins>Color Theme (Multiple Fields).
4. Click Choose Fields.
5. Filter by typing in the "hisp" in the edit box.
6. Highlight [Hispanic Origin], [Not Hispanic White], and [Not Hispanic_Black].
7. Click Add>> and click OK.
8. In the Denominator drop-down list choose Population.
9. Leave the number of classes at 4, and enter 25, 50, 75, and 100 in the High % column.
10. Click OK.

Tips for Choosing the Denominator

The Color Theme (Multiple Fields) add-in determines the percentages of each field that you use to determine which field is contains the plurality for an area. When comparing fields of populations or households the demoninator is straightforward. In other cases, you may need to create a formula field that contains the total value for the denominator. For example, you may have fields for counties that contain the Democrat, Republican, and Other votes from an election. To create a plurality theme map showing the party receiving the most votes in each county, you will first need to create a "Total Votes" formula field that is the sum of those three fields to use as the denominator.

Tips for Setting the Ranges

You may want to adjust the values used in the ranges depending on the data that you are mapping. Suppose that you have fields with the number of McDonald's, Burger King, Wendy's, and Sonic stores in each state and a formula field that is the sum of the four stores:

• If you want to know which is the predominent store in each state, then at least one store must have greater than 25% of the market so the first range should not be less than 25%. In this case, you may want to use ranges of 0-30%, 30-40%, 40-50%, and 50-100%.
• On the other hand, you may want to know, aside from McDonald's, what is the predominant store in each state. In this case, you could have a chain with a plurality that is less than 25%, so you may want to use ranges of 0-10%, 10-25%, 25-50%, and 50-100%.

If there is not much variation within the ranges for your theme, you may want to run the add-in several times adjusting the values in the ranges until you get a plurality map that is more meaningful.